METHOD OF INTEGRATING SELECT GATE SOURCE AND MEMORY HOLE FOR THREE-DIMENSIONAL NON-VOLATILE MEMORY DEVICE

摘要

A method of fabricating a semiconductor device, such as a three-dimensional NAND memory string, includes forming a carbon etch stop layer having a first width over a major surface of a substrate, forming a stack of alternating material layers over the etch stop layer, etching the stack to the etch stop layer to form a memory opening having a second width at a bottom of the memory opening that is smaller than the width of the etch stop layer, removing the etch stop layer to provide a void area having a larger width than the second width of the memory opening, forming a memory film over a sidewall of the memory opening and in the void area, and forming a semiconductor channel in the memory opening such that the memory film is located between the semiconductor channel and the sidewall of the memory opening.

主权项

1. A method of fabricating a memory device, comprising:
forming a carbon etch stop layer having a first width dimension over a major surface of a substrate; forming a stack of alternating layers of a first material and a second material different from the first material over the carbon etch stop layer; etching the stack through a mask to the carbon etch stop layer to form a memory opening having a second width dimension at a bottom of the memory opening proximate to the carbon etch stop layer that is smaller than the first width dimension of the carbon etch stop layer; removing the carbon etch stop layer to provide a void area between the bottom of the memory opening and a top surface of a protrusion comprising a semiconductor material, the void area having a larger width dimension than the second width dimension of the memory opening; forming at least a portion of a memory film over a sidewall of the memory opening and in the void area; and forming a semiconductor channel in the memory opening such that the memory film is located between the semiconductor channel and the sidewall of the memory opening.